Vice-Admiral The Hon. John Byron, RN (November 8, 1723 – April 10, 1786) is a British Royal Navy officer and politician.

He is known as Foul-weather Jack because of his frequent encounters with bad weather at sea.

As a midshipman, he sails in the squadron under George Anson on his voyage around the world, though Byron makes it to southern Chile, and returns to England with the captain of HMS Wager.

He is governor of Newfoundland following Hugh Palliser, who leaves in 1768.

He circumnavigates the world as a commodore with his own squadron in 1764-1766.

He fights in battles in The Seven Years' War and the American Revolution.

He rises to Vice Admiral of the White before his death in 1786.

His grandsons include the poet George Gordon Byron and George Anson Byron, admiral and explorer, who are the 6th and 7th Baron Byron, respectively.